Cytopathology of false negatives preceding cervical carcinoma

False Negative Results in Cervical Cancer Screening-Risks, Reasons and Implications for Clinical Practice and Public Health

False negative (FN) results in cervical cancer (CC) screening pose serious risks to women. We present a comprehensive literature review on the risks and reasons of obtaining the FN results of primary CC screening tests and triage methods and discuss their clinical and public health impact and implications. Misinterpretation or true lack of abnormalities on a slide are the reasons of FN results in cytology and p16/Ki-67 dual-staining. For high-risk human papillomavirus (HPV) molecular tests, those include: truly non-HPV-associated tumors, lesions driven by low-risk HPV types, and clearance of HPV genetic material before sampling. Imprecise disease threshold definition lead to FN results in visual inspection with acetic acid. Lesions with a discrete colposcopic appearance are a source of FN in colposcopic procedures. For FAM19A4 and hsa-miR124-2 genes methylation, those may originate from borderline methylation levels. Histological misinterpretation, sampling, and laboratory errors also play a role in all types of CC screening, as well as reproducibility issue, especially in methods based on human-eye evaluation. Primary HPV-based screening combined with high quality-assured immunocytochemical and molecular triage methods seem to be an optimal approach. Colposcopy with histological evaluation remains the gold standard for diagnosis but requires quality protocols and assurance measures.

Risk factors of cervical cancer after a negative cytological diagnosis in Polish cervical cancer screening programme

Risk factors of cervical cancer (CC) development are well investigated, however, those influencing the risk of a potential false negative cytology preceding diagnosis of an invasive CC are not. We have aimed to explore these factors according to the data from Organised Cervical Cancer Screening Programme (OCCSP) in Poland. A total of 2.36 million of Pap tests sampled in 2010–2012 within OCCSP were merged with the Polish National Cancer Registry to identify CC cases after abnormal cytology and after normal cytology within 3 years of screening. Of 1460 invasive CCs, 1025 were preceded by abnormal and 399 by normal cytology result. Multivariate logistic analysis indicated that the presence of microorganisms in the Pap (OR = 2.18, 95% CI 1.65–2.87), evaluation by smaller (below 9000 slides processed per year) laboratories (OR = 1.60, 95% CI 1.22–2.09) and non‐squamous histology of cancer increased the odds for a potential false negative result (OR = 3.39, 95% CI 2.37–4.85 for adenocarcinoma, OR = 1.99, 95% CI 1.11–3.55 for other types of carcinoma), whereas cervical ectropion, other macroscopic changes on the cervix and smoking decrease the odds for a potential false negative Pap test result preceding CC (OR = 0.61, 95% CI 0.45–0.82, OR = 0.41, 95% CI 0.25–0.67, OR = 0.60, 95% CI 0.46–0.78, respectively). Proper triage of women with microscopic signs of microorganisms in the Pap smear should be reconsidered and cytology should be assessed in laboratories processing over 9000 slides annually to decrease the odds for negative Pap test result in 2 years before CC diagnosis. Information on macroscopic changes on the cervix provided to cytomorphologist may reduce the risk of a potential false negative cytology result.

Cervical Cancer in Women with Normal Papanicolaou Tests: A Korean Nationwide Cohort Study

Purpose

This study aimed to evaluate the risk of cervical cancer diagnosed within 1 year after the last of multiple consecutive normal Papanicolau (Pap) tests.

Materials and Methods

The database of the National Health Insurance Service was used. We obtained Pap test data for 11,052,116 women aged 30–79 between 2007–2012. The cumulative incidence rates and 5-year overall survival rates of cervical cancer diagnosed within 1 year after the last normal Pap test were compared between women with one (N1), two (N2), and three consecutive normal Pap tests (N3). Women who did not receive a Pap test during the study period were assigned in the N0 group.

Results

The 1-year cumulative incidence rates of cervical cancer were 58.9, 24.6, 20.3, and 14.2 per 10⁵ in the N0, N1, N2, and N3 groups, respectively. Compared to the N1 group, the risk of cervical cancer diagnosed within 1 year of the last normal Pap test decreased by 17% (relative risk [RR], 0.825; 95% confidence interval [CI], 0.716 to 0.951) in the N2 group and 42% (RR, 0.578; 95% CI, 0.480 to 0.695) in the N3 group. However, the 5-year survival rate in women diagnosed with cervical cancer within 1 year of the last normal Pap test in the N3 group was not higher than that of the N1 group (79.6% vs. 81.3%, p=0.706).

Conclusion

As normal Pap tests are consecutively repeated, cervical cancer risk significantly decreases. However, previous consecutive normal Pap tests are not associated with improving survival outcomes in women shortly diagnosed with cervical cancer after the last normal Pap test.

Biomarkers in Cervical Cancer

Cervical cancer, a potentially preventable disease, remains the second most common malignancy in women worldwide. Human papillomavirus (HPV) is the single most important etiological agent in cervical cancer, contributing to neoplastic progression through the action of viral oncoproteins, mainly E6 and E7. Cervical screening programs using Pap smear testing have dramatically improved cervical cancer incidence and reduced deaths, but cervical cancer still remains a global health burden. The biomarker discovery for accurate detection and diagnosis of cervical carcinoma and its malignant precursors (collectively referred to as high-grade cervical disease) represents one of the current challenges in clinical medicine and cytopathology.

Mesoscale imaging with cryo-light and X-rays: Larger than molecular machines, smaller than a cell

In the context of cell biology, the term mesoscale describes length scales ranging from that of an individual cell, down to the size of the molecular machines. In this spatial regime, small building blocks self-organise to form large, functional structures. A comprehensive set of rules governing mesoscale self-organisation has not been established, making the prediction of many cell behaviours difficult, if not impossible. Our knowledge of mesoscale biology comes from experimental data, in particular, imaging. Here, we explore the application of soft X-ray tomography (SXT) to imaging the mesoscale, and describe the structural insights this technology can generate. We also discuss how SXT imaging is complemented by the addition of correlative fluorescence data measured from the same cell. This combination of two discrete imaging modalities produces a 3D view of the cell that blends high-resolution structural information with precise molecular localisation data.

Morphometric Analysis of Thyroid Follicular Cells with Atypia of Undetermined Significance

BACKGROUND

Atypia of undetermined significance (AUS) is a category that encompasses a heterogeneous group of thyroid aspiration cytology. It has been reclassified into two subgroups based on the cytomorphologic features: AUS with cytologic atypia and AUS with architectural atypia. The nuclear characteristics of AUS with cytologic atypia need to be clarified by comparing to those observed in Hashimoto thyroiditis and benign follicular lesions.

METHODS

We selected 84 cases of AUS with histologic follow-up, 24 cases of Hashimoto thyroiditis, and 26 cases of benign follicular lesions. We also subcategorized the AUS group according to the follow-up biopsy results into a papillary carcinoma group and a nodular hyperplasia group. The differences in morphometric parameters, including the nuclear areas and perimeters, were compared between these groups.

RESULTS

The AUS group had significantly smaller nuclear areas than the Hashimoto thyroiditis group, but the nuclear perimeters were not statistically different. The AUS group also had significantly smaller nuclear areas than the benign follicular lesion group; however, the AUS group had significantly longer nuclear perimeters. The nuclear areas in the papillary carcinoma group were significantly smaller than those in the nodular hyperplasia group; however, the nuclear perimeters were not statistically different.

CONCLUSIONS

We found the AUS group to be a heterogeneous entity, including histologic follow-up diagnoses of papillary carcinoma and nodular hyperplasia. The AUS group showed significantly greater nuclear irregularities than the other two groups. Utilizing these features, nuclear morphometry could lead to improvements in the accuracy of the subjective diagnoses made with thyroid aspiration cytology.

A feasibility study to identify proteins in the residual Pap test fluid of women with normal cytology by mass spectrometry-based proteomics

BACKGROUND

The proteomic analysis of body fluids is a growing technology for the identification of protein biomarkers of disease. Given that Papanicolaou tests (Pap tests) are routinely performed on over 30 million women annually in the U.S. to screen for cervical cancer, we examined the residual Pap test fluid as a source of protein for analysis by mass spectrometry (MS). In the liquid-based Pap test, cervical cells are collected from the ectocervix and placed into an alcohol-based fixative prior to staining and pathologic examination. We hypothesized that proteins shed by cells of the female genital tract can be detected in the Pap test fixative by MS-based proteomic techniques. We examined the feasibility of using residual fluid from discarded Pap tests with cytologically "normal" results to optimize sample preparation for MS analysis. The protein composition of the cell-free Pap test fluid was determined by silver staining of sodium dodecyl sulfate -polyacrylamide gels, and the abundance of serum proteins was examined by Western immunoblot using an antibody against human serum albumin. Both pooled and individual samples were trypsin digested and analyzed by two-dimensional MS/MS. Proteins were identified by searching against the Human Uniprot database, and characterized for localization, function and relative abundance.

RESULTS

The average volume of the residual Pap test fluid was 1.5 ml and the average protein concentration was 0.14 mg/ml. By Western immunoblot we showed that the amount of albumin in each sample was significantly reduced compared to normal serum. By MS/MS, we identified 714 unique proteins in pooled Pap test samples and an average of 431 proteins in individual samples. About 40% of the proteins identified were extracellular or localized to the plasma membrane. Almost 20% of the proteins identified were involved in immunity and defense, characteristic of the healthy cervical-vaginal proteome. By merging the protein sets from the individual and pooled Pap test samples, we created a "Normal Pap test Core Proteome" consisting of 153 proteins.

CONCLUSIONS

Residual Pap test fluid contains a sufficient amount of protein for analysis by MS and represents a valuable biospecimen source for the identification of protein biomarkers for gynecological diseases.

PAX8: a sensitive and specific marker to identify cancer cells of ovarian origin for patients prior to neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy followed by cytoreduction surgery has been used where an accurate cytologic or pathologic diagnosis is usually required before the initiation of neoadjuvant chemotherapy. However, it is difficult to make definitive diagnosis of presence of cancer cells, particularly gynecologic versus non-gynecologic origin, from those ascites specimens due to the absence of specific biomarkers of gynecologic cancers. In the present study, we evaluated if, in addition to the routine morphologic diagnosis, the biomarker PAX8 could be useful in recognition of ovarian epithelial cancer cells prior to the neoadjuvant chemotherapy.

METHODS

Two hundred and two cytology specimens including 120 pretreatment ovarian cancer samples, 60 benign controls, and 22 malignant non-gynecologic cases were studied. All cytology slides were morphologically reviewed in a blinded fashion without knowing corresponding pathology diagnosis, if present. A total of 168 cytology specimens with a cell block were stained with PAX8 and Calretinin. These included patients with potential for ovarian cancer neoadjuvant chemotherapy (n=96), metastatic cancers (n=22), and benign controls (n=50).

RESULTS

Among the 96 ascitic samples prior to neoadjuvant chemotherapy, 76 (79%) showing morphologic features consistent with cancers of ovarian primary were all PAX+/Calretinin-. The remaining 20 (21%) cases were positive for adenocarcinoma, but morphologically unable to be further classified. Among the 22 metastatic cancers into the pelvis, one case with PAX8+/Calretinin- represented a renal cell carcinoma and the remaining 21 PAX8-/Calretinin- metastatic cancers were either breast metastasis (n=4) and the metastasis from gastrointestinal tract (n=17). Among the 50 benign control pelvic washing cases, 5 PAX8+/Calretinin-cases represented endosalpingiosis (n=4) and endometriosis (n=1), 25 PAX8-/Calretinin+cases showed reactive mesothelial cells, and the remaining 20 specimens with PAX8-/Calretinin- phenotype typically contained inflammatory or blood cells without noticeable diagnostic epithelia.

CONCLUSIONS

PAX8 identifies all Müllerian derived benign or malignant epithelia. When combining with Calretinin, PAX8 is a sensitive marker to diagnose the carcinomas of ovarian origin, which will be ideal to be used for those patients with a possible advanced ovarian cancer prior to receiving neoadjuvant chemotherapy.

Cervical screening: why young women should be encouraged to be screened

BACKGROUND

The English National Health Service Cervical Screening Programme (NHSCSP) recommendation not to offer cervical screening to women aged 20-24 years is considered in the context of national rates of cervical intraepithelial neoplasia grade 3 (CIN3) and invasive cervical carcinoma, falling screening coverage in young women, detection of screen-detected invasive cancers and risks of excisional treatment of CIN.

METHODS

Registrations of invasive and in situ cervical carcinoma were obtained from the Office for National Statistics, data on screening coverage and cytology results from the NHSCSP website and data on screen-detected cancers from an audit at Guy's & St Thomas' NHS Foundation Trust (GSTFT).

RESULTS

Before and after the introduction of organised screening in England, CIN3 was primarily detected in women aged 20-39 years. Increasing rates of CIN3 were recorded in women aged 20-24 years during the last decade (3000-4000 cases per year) despite falling screening coverage. The peak incidence of invasive cancer in screening age groups is now 35-39 years. At GSTFT in 1999-2006, 24 of 32 cancers (75%) in women aged 20-34 years were screen-detected and that percentage declined in subsequent 15-year age bands (p < or =0.0001).

DISCUSSION AND CONCLUSIONS

Delaying the age for screening eligibility carries a risk of CIN becoming more extensive, and therefore more difficult to excise, as well as a risk of progression. The NHSCSP should reconsider its decision and encourage young women to be screened, not excluding those aged 20-24 years. Facilities for taking the tests should be made more convenient. Women should be informed that low-grade CIN is potentially reversible and may safely be monitored. Cervical screening also provides an opportunity for education on healthy lifestyles and safer sex while treatment should be reserved for high-grade CIN.

[Cytological history of cases of invasive cervical cancer diagnosed in France in 2006]

OBJECTIVE

After a significant decrease of the incidence of invasive cervical cancer with the practice of cytologic screening, the numbers remain the same nowadays. To explain the reasons for that, we performed a survey of the cases of invasive cervical cancer observed in France in 2006.

MATERIAL AND METHOD

A questionnaire about screening practice was sent to every member of the French Society of Colposcopy (SFCPCV) to fill out for every invasive cancer diagnosed in 2006.

RESULTS

Five hundred and twenty-four cases were collected: 2/3 of them never had a pap smear or were under screened. Indeed 27% had a labelled normal smear in the last three years.

DISCUSSION AND CONCLUSION

As many others, this study shows that the first risk factor remains the lack of screening. But, 27% are false negative pap smears and it is even 45% under 45 years. The first thing to do is an organized mass screening but the increasing number of false negatives raises the question of the quality control of the cytology, or else to turn to a new test.

Human papillomavirus testing and molecular markers of cervical dysplasia and carcinoma

Cervical cancer is the second most common cancer in women worldwide. Human papillomavirus (HPV) is the etiologic agent for the vast majority of premalignant and malignant lesions, and high-risk HPV types can be detected in almost all cases of cervical dysplasia and carcinoma. HPV testing has been widely adopted for the triage of patients after a cervical cytology screening test (Papanicolaou smear or liquid-based cervical cytology such as ThinPrep or SurePath) interpretation of atypical squamous cells of undetermined significance (ASCUS), and HPV testing is increasingly used for screening in conjunction with cervical cytology. Although cervical cytology is a highly effective screening test for cancer, it has limited specificity for clinically significant lesions in cases with low-grade cytologic abnormalities. Up to a quarter of all patients may have a false-negative result on the basis of cervical cytology testing alone. This review focuses on HPV testing methods and molecular markers and their clinical relevance. HPV testing and surrogate molecular markers of HPV infection (p16INK4a) may help identify cases that are associated with underlying high-grade premalignant or malignant lesions and may also reduce aggressive treatment of patients with low-grade lesions.

Trouble in the office: liability issues in ambulatory care

Most clinicians are keenly aware of the liability risks associated with adverse birth outcomes for mother and/or infant. This level of awareness and concern also needs to extend to the day-to-day management of office practice. Clinicians who care for healthy women and their families may see abnormalities infrequently. The low yield of abnormal results means that close monitoring is essential to prevent overlooking the rare abnormal finding. This article focuses on three areas of liability risk for midwives and others who practice in the ambulatory setting: 1) inadequate tracking of test and referral results, 2) failure to diagnose, and 3) poor communication. Although none of these issues are limited to the ambulatory setting, only office practice is addressed in this article.

Prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with cytologically negative Pap smear

OBJECTIVE

To study the prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with negative Pap smears in identifying women with underlying cervical squamous intra-epithelial (SIL) lesions.

METHODS

A total of 3300 women who were attending the Gynecology OPD of Lok Nayak Hospital, one of the major government tertiary hospitals in New Delhi, were screened during a 1-year study period, and 2079 (63%) of them were found to have cytologically negative Pap smear with inflammation and the rest (37%) also had negative Pap report but without inflammation. Hundred and sixty of these sexually active women aged between 20 and 60 years were randomly selected, and were investigated by colposcopy and a guided biopsy was done wherever required. HPV types 16 and 18 DNA was detected in scraped cervical cells from all women using type-specific primers in polymerase chain reaction (PCR).

RESULTS

The high-risk HPV (type 16 and 18) prevalence by PCR was found to be 10% (16/160). Histopathological findings were obtained in 123 women, out of which 15 had LSIL and four had HSIL. High-risk HPV types 16/18 could be detected in nine out of these 19 (47.3%) squamous intra-epithelial lesions (p < 0.00008) which includes two out of the four women (50%) having HSIL, while only seven out of 104 (6.7%) of the subjects with normal (negative) Pap reports (p = 0.03) had infection of high-risk HPV.

CONCLUSION

The results indicate that about 10% of women who show a negative Pap smear, but have inflammation are positive for high-risk HPV types 16/18 and about 15% harbor squamous intra-epithelial lesions. It is suggested that high-risk HPV detection can be utilized as an adjunct to routine cytology screening programs to identify 'high risk' women who have concurrently negative Pap smears but may harbor oncogenic HPV infection and/or more likely to develop CIN lesions.

Right-Sided Ectocervical Lesions May Be Associated with False-Negative Cytology Among Women with Histologic Cervical Intraepithelial Neoplasia 2 or 3

BACKGROUND

The association between the location of an ectocervical lesion and the sensibility of cytologic screening has not been adequately evaluated.

METHODS

We evaluated the proportion of false-negative cytologic interpretations using three independent cytologic interpretations (conventional, PapNet, and ThinPrep) according to lesion location in 111 women with histologic cervical intraepithelial neoplasia 2 or 3 of a population-based study of cervical neoplasia conducted in Guanacaste, Costa Rica. Semiquantitative measures of human papillomavirus viral load were also considered.

RESULTS

Lesions on a women's right ectocervix were associated with more frequent false-negative results than lesions on left ectocervix for each of the cytologic methods or when the most severe interpretation was considered (p = .004). Right-sided lesions had nonsignificantly lower viral loads than left-sided lesions (p = .2).

CONCLUSIONS

Cervical intraepithelial neoplasia 2 or 3 located on the right side of the cervix may be poorly sampled with broom samplers in some settings, resulting in false-negative cytologic results.

In vitro conventional cytology historical strengths and current limitations

Despite the fact that cervical cytology screening programs have dramatically reduced the prevalence of cervical cancer in the US, women continue to develop and die from the disease. The most important observation contributing to this failing is that 60% of women with invasive cancer have not had a Pap smear in the previous 5 years (or have never had one). The most clinically effective and cost effective approach to reducing the incidence of cervical cancer is to screen the unscreened population. Recent evidence has also noted that the sensitivity of conventional cytology is also much lower than was previously believed. Much recent investigation has been directed at identifying the reasons for this low sensitivity and identifying ways to improve it. Only by improving the sensitivity of cervical cancer screening and participation in screening programs can the prevalence, morbidity, and mortality from cervical cancer be further reduced.

Cervical smear interpretations in women with a histologic diagnosis of severe dysplasia: factors associated with discrepant interpretations

BACKGROUND

Because most low-grade squamous intraepithelial lesions (LSIL) regress spontaneously, the appropriate follow-up of women with a cytologic diagnosis of LSIL has engendered discussion. This retrospective study was undertaken to assess the feasibility of limiting colposcopy to women with cytologic interpretations of high-grade squamous intraepithelial lesions (HSIL) in a high-risk population.

METHODS

The pathology computer files (including files from January to December 1997) of The University Hospital, University of Oklahoma Health Sciences Center, revealed 197 women whose histologic samples were coded as severe dysplasia. Of these, 138 had a cervical smear interpreted in our laboratory before the colposcopic visit. On review, the tissue samples of 119 women met consensus criteria for severe dysplasia.

RESULTS

Original cytologic diagnoses for 119 cytologic smears included 80 (62.7%) that were interpreted as HSIL. After retrospective review, 28 cases with LSIL or less were reclassified as HSIL and were considered to be discrepant for the purpose of this study. Major confounding factors in the original categorization include lack of consistency among the pathologists for the interpretation of metaplastic patterns and specimen adequacy, particularly air-drying artifact. Eleven cases (10.2%) did not have cells identifiable as HSIL because of sampling error and/or severe air-drying artifact.

CONCLUSIONS

These results indicate that a substantial number of histologically verified cases of severe dysplasia can have a smear interpretation of LSIL or less. The factors that hampered recognition of the true severity of the lesion in this series were identified and tabulated.

Analysis of telomerase as a diagnostic biomarker of cervical dysplasia and carcinoma

Telomerase expression is a potentially important marker of high-grade cervical dysplasia and squamous cell carcinoma (SCC). The routine practice of cervical cytology is limited by problems of false negative diagnoses as well as by poor specificity for clinically significant lesions in patients with low-grade cytologic abnormalities. Telomerase is widely expressed in most SCCs as well as in a high proportion of high-grade squamous intraepithelial lesions. Histochemical studies have confirmed that telomerase is expressed in the lower portions of normal or metaplastic squamous mucosa but that telomerase positive cells extend into the upper epithelial layers in cases of high-grade dysplasia. Since the cervical smear samples the uppermost cell layers of the cervical mucosa, but does not normally include cells derived from the lower layers of the squamous mucosa, the detection of telomerase in exfoliated cells of the cervical smear may have specificity for clinically significant lesions. The analysis of hTR, hTERT, and telomerase activity are complicated by a number of technical factors that may lead to either false negative or false positive test results. Thus, the practical application of telomerase analysis as a diagnostic adjunct for cervical cytopathology may depend on the development of more reliable and sensitive assay systems, possibly formatted for cytochemical applications.

Presentation and screening history of indigent women with cervical cancer: implications for prevention

OBJECTIVE

To identify missed opportunities for screening and early diagnosis of indigent patients with cervical cancer.

MATERIALS AND METHODS

The authors conducted a retrospective review of charts and databases for demographic information, presenting symptoms, staging data, prior health system contacts, and Papanicolaou smears. Women with cervical cancer were evaluated at an urban public hospital between July 1, 1994, and March 31, 1998.

RESULTS

Among 177 women with cervical cancer where record could be retrieved, 82 were in stage I, 49 were in II, 25 were in III, and 11 were in IV. Symptoms attributable to cancer were present in 153 (86%) cases, but asymptomatic women were more likely to have stage I cancers (21 of 23 versus 70 of 153, p < .0005). Only 54 (31%) women had prior visits recorded, with emergency services the most common site for visits. Only 23 (43%) of these had prior cytology recorded, four of which were false negatives. Stage I cancers were found in 18 (78%) of these women, compared to 13 (42%) of the 31 women previously seen without a recorded Papanicolaou smear (p < .02). Women with prior visits to gynecology services or clinics were more likely to have Papanicolaou smears recorded (10 of 13 versus 9 of 32 at other sites, p < .0005) but not more likely to have stage I cancer (10 of 13 versus 20 of 41, p = .08).

CONCLUSIONS

Further reductions in cervical cancer rates are likely to require outreach, screening in nontraditional sites, and refinement of public sector screening programs.

The clinical significance of the poor correlation of cervical dysplasia and cervical malignancy with referral cytologic results

OBJECTIVE

We prospectively studied the diagnostic utility of our Bethesda system-based cervical cytology screening program with colposcopy and biopsy as the criterion standard.

STUDY DESIGN

We prospectively collected and studied the correlation of cytologic, colposcopic, and histologic data in women referred for colposcopic examination because of "nonnormal" cytologic results or other risk factors.

RESULTS

We found that 771 of 5585 initial colposcopic visits yielded high-grade (cervical intraepithelial neoplasia II or worse) biopsies (13.8% prevalence); 13 showed invasive cancer (0.23% prevalence). Only 132 of 771 cases of high-grade dysplasia (17%) and 5 of 13 cases of invasive cancer (38%) followed Papanicolaou smears suggesting high-grade intraepithelial lesions or cancer, with 77% being discovered after "minor" Papanicolaou smear abnormalities. High-grade disease or cancer was confirmed in 1 of 2 high-grade or cancer Papanicolaou referrals and in 1 of 11 referrals with atypical squamous cells of undetermined significance.

CONCLUSION

Papanicolaou smears, especially those that are low grade, should not be equated with histologic sampling in association with poor cytohistopathologic correlation. Most high-grade dysplasias and cancers occur in women with either minor Papanicolaou smear abnormalities or visible lower genital tract lesions or both. Colposcopy for women with any "nonnormal" screening result is feasible.